What Should Be Adequate PRP Dose for an Effective Treatment? An In-Vitro Experimental Study on the Skin

2021 ◽  
Author(s):  
Metin Görgü ◽  
Ali Gökkaya ◽  
Ertuğrul Karanfil
Keyword(s):  
Horizontal Plane ◽  
Unit Area ◽  
Platelet Rich Plasma ◽  
Clinical Results ◽  
Preparation Methods ◽  
Applied Dose ◽  
Platelet Concentration ◽  
Needle Diameter ◽  
Different Doses

Abstract Background The clinical results of many studies on platelet-rich plasma (PRP) differ because there is a lack of standardization in PRP preparation and administration, as well as many variables such as PRP preparation methods, platelet concentration, and platelet activation. Objectives The aim of this study was to investigate a different variable that will affect PRP application results. How much PRP should be injected into the unit area of tissue for an effective PRP treatment? Methods The study was performed on fresh surplus tissues of 20 patients that were discarded in abdominoplasty and mammoplasty operations. 9 areas that were 4cm 2 in size were marked on the skin. Fluorescein-stained PRP was injected intradermally by using 3 different gauge needles and 3 different doses (0.01, 0.03, and 0.05 ml). After injections, spreads of the fluorescent dye-covered areas in horizontal and vertical planes were measured and compared. For the horizontal plane measurements, the dye spread was measured, first from the surface of skin and a second measurement was done from the dermal surface of skin. In addition, the width and depth of the dye spread in the dermis were measured from vertical sections. Results Changing the needle diameter does not affect the width or depth (thickness) of the PRP spread in the dermis. Increasing the applied dose to 0.03 ml increases the spread to the width and depth (thickness). Conclusions In research for evaluating the effectiveness of PRP treatments, it is necessary to report the volume of PRP to be applied per unit tissue.

Anti-Inflammatory Effects of Novel Standardized Platelet Rich Plasma Releasates on Knee Osteoarthritic Chondrocytes and Cartilage in vitro

2019 ◽  
Vol 20 (11) ◽  
pp. 920-933 ◽  
Author(s):  
Lucía Gato-Calvo ◽  
Tamara Hermida-Gómez ◽  
Cristina R. Romero ◽  
Elena F. Burguera ◽  
Francisco J. Blanco
Keyword(s):  
Gene Expression ◽  
Ex Vivo ◽  
Platelet Rich Plasma ◽  
Cartilage Explants ◽  
Ex Vivo Model ◽  
Chondrocyte Viability ◽  
Platelet Concentration ◽  
The Absolute ◽  
Anti Inflammatory

Background: Platelet Rich Plasma (PRP) has recently emerged as a potential treatment for osteoarthritis (OA), but composition heterogeneity hampers comparison among studies, with the result that definite conclusions on its efficacy have not been reached. Objective: 1) To develop a novel methodology to prepare a series of standardized PRP releasates (PRP-Rs) with known absolute platelet concentrations, and 2) To evaluate the influence of this standardization parameter on the anti-inflammatory properties of these PRP-Rs in an in vitro and an ex vivo model of OA. Methods: A series of PRPs was prepared using the absolute platelet concentration as the standardization parameter. Doses of platelets ranged from 0% (platelet poor plasma, PPP) to 1.5·105 platelets/µl. PRPs were then activated with CaCl2 to obtain releasates (PRP-R). Chondrocytes were stimulated with 10% of each PRP-R in serum-free culture medium for 72 h to assess proliferation and viability. Cells were co-stimulated with interleukin (IL)-1β (5 ng/ml) and 10% of each PRP-R for 48 h to determine the effects on gene expression, secretion and intra-cellular content of common markers associated with inflammation, catabolism and oxidative stress in OA. OA cartilage explants were co-stimulated with IL-1β (5 ng/ml) and 10% of either PRP-R with 0.75·105 platelets/µl or PRP-R with 1.5·105 platelets/µl for 21 days to assess matrix inflammatory degradation. Results: Chondrocyte viability was not affected, and proliferation was dose-dependently increased. The gene expression of all pro-inflammatory mediators was significantly and dose-independently reduced, except for that of IL-1β and IL-8. Immunoblotting corroborated this effect for inducible NO synthase (NOS2). Secreted matrix metalloproteinase-13 (MMP-13) was reduced to almost basal levels by the PRP-R from PPP. Increasing platelet dosage led to progressive loss to this anti-catabolic ability. Safranin O and toluidine blue stains supported the beneficial effect of low platelet dosage on cartilage matrix preservation. Conclusion: We have developed a methodology to prepare PRP releasates using the absolute platelet concentration as the standardization parameter. Using this approach, the composition of the resulting PRP derived product is independent of the donor initial basal platelet count, thereby allowing the evaluation of its effects objectively and reproducibly. In our OA models, PRP-Rs showed antiinflammatory, anti-oxidant and anti-catabolic properties. Platelet enrichment could favor chondrocyte proliferation but is not necessary for the above effects and could even be counter-productive.

scholarly journals Development of Autologous Platelet-Rich Plasma Mixed-Microfat as an Advanced Therapy Medicinal Product for Intra-Articular Injection of Radio-Carpal Osteoarthritis: From Validation Data to Preliminary Clinical Results

2019 ◽  
Vol 20 (5) ◽  
pp. 1111 ◽  
Author(s):  
Alice Mayoly ◽  
Aurélie Iniesta ◽  
Caroline Curvale ◽  
Najib Kachouh ◽  
Charlotte Jaloux ◽  
...  
Keyword(s):  
Medicinal Product ◽  
Platelet Rich Plasma ◽  
Stromal Vascular Fraction ◽  
Clinical Results ◽  
Advanced Therapy Medicinal Product ◽  
Validation Data ◽  
Painful Condition ◽  
Advanced Therapy ◽  
Functional Scores

Wrist osteoarthritis (OA) is one of the most common conditions encountered by hand surgeons with limited efficacy of non-surgical treatments. The purpose of this study is to describe the Platelet-Rich Plasma (PRP) mixed-microfat biological characteristics of an experimental Advanced Therapy Medicinal Product (ATMP) needed for clinical trial authorization and describe the clinical results obtained from our first three patients 12 months after treatment (NCT03164122). Biological characterization of microfat, PRP and mixture were analysed in vitro according to validated methods. Patients with stage four OA according to the Kellgren Lawrence classification, with failure to conservative treatment and a persistent daily painful condition >40 mm according to the visual analog scale (VAS) were treated. Microfat-PRP ATMP is a product with high platelet purity, conserved viability of stromal vascular fraction cells, chondrogenic differentiation capacity in vitro and high secretion of IL-1Ra anti-inflammatory cytokine. For patients, the only side effect was pain at the adipose tissue harvesting sites. Potential efficacy was observed with a pain decrease of over 50% (per VAS score) and the achievement of minimal clinically important differences for DASH and PRWE functional scores at one year in all three patients. Microfat-PRP ATMP presented a good safety profile after an injection in wrist OA. Efficacy trials are necessary to assess whether this innovative strategy could delay the necessity to perform non-conservative surgery.

scholarly journals Centrifugation Conditions in the L-PRP Preparation Affect Soluble Factors Release and Mesenchymal Stem Cell Proliferation in Fibrin Nanofibers

Molecules ◽  
2019 ◽  
Vol 24 (15) ◽  
pp. 2729 ◽  
Author(s):  
Melo ◽  
Luzo ◽  
Lana ◽  
Santana
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor ◽  
Platelet Rich Plasma ◽  
Clinical Practices ◽  
Soluble Factors ◽  
Tnf Α ◽  
Platelet Concentration ◽  
Tgf Β1

Leukocyte and platelet-rich plasma (L-PRP) is an autologous product that when activated forms fibrin nanofibers, which are useful in regenerative medicine. As an important part of the preparation of L-PRP, the centrifugation parameters may affect the release of soluble factors that modulate the behavior of the cells in the nanofibers. In this study, we evaluated the influences of four different centrifugation conditions on the concentration of platelets and leukocytes in L-PRP and on the anabolic/catabolic balance of the nanofiber microenvironment. Human adipose-derived mesenchymal stem cells (h-AdMSCs) were seeded in the nanofibers, and their viability and growth were evaluated. L-PRPs prepared at 100× g and 100 + 400× g released higher levels of transforming growth factor (TGF)-β1 and platelet-derived growth factor (PDGF)-BB due to the increased platelet concentration, while inflammatory cytokines interleukin (IL)-8 and tumor necrosis factor (TNF)-α were more significantly released from L-PRPs prepared via two centrifugation steps (100 + 400× g and 800 + 400× g) due to the increased concentration of leukocytes. Our results showed that with the exception of nanofibers formed from L-PRP prepared at 800 + 400× g, all other microenvironments were favorable for h-AdMSC proliferation. Here, we present a reproducible protocol for the standardization of L-PRP and fibrin nanofibers useful in clinical practices with known platelet/leukocyte ratios and in vitro evaluations that may predict in vivo results.

scholarly journals Evaluation of allogeneic freeze-dried platelet lysate in cartilage exposed to interleukin 1-β in vitro

2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Livia Camargo Garbin ◽  
C. Wayne McIlwraith ◽  
David D. Frisbie
Keyword(s):  
Musculoskeletal Diseases ◽  
Platelet Rich Plasma ◽  
Autologous Blood ◽  
Interleukin 1 ◽  
Platelet Lysate ◽  
Freeze Dried ◽  
Platelet Concentration ◽  
High Concentrations ◽  
Disease Modifying Treatment

Abstract Background Platelet-rich plasma (PRP) as well as other platelet-derived products have been used as a potential disease-modifying treatment for musculoskeletal diseases, such as osteoarthritis (OA). The restorative properties of such products rely mainly on the high concentrations of growth factors, demonstrating encouraging results experimentally and clinically. Yet, the autologous blood-derived nature of the PRP product lead to limitations that precludes it’s widespread use. The main limitations for PRP use are; product variability, the need for minimum laboratory settings in most cases, and the need for storage at low temperatures to preserve its properties. Based on these limitations, the objective of this study was to investigate an allogeneic off-the-shelf platelet lysate (PL) in cartilage exposed to interleukin 1β (IL-1β). For this purpose, blood and cartilage were harvested from eight skeletally mature and healthy horses. Blood was processed into PL aliquots and divided into three groups (Frozen, Freeze-dried and Filtered freeze-dried), used in autologous and allogeneic conditions and in three different concentrations (1.5, 3 and 6-fold). Different PL preparations were then applied in cartilage culture with interleukin-1 beta and cultured for 10 days. Cartilage and media samples were collected and analyzed for total GAG and 35SO4-labeled GAG content. Results No significant differences between the controls and PL groups in cartilage and media were demonstrated. The effects of PL on cartilage matrix were concentration dependent and intermediate concentrations (3-fold) in PL showed increased 35SO4-labelled GAG in cartilage. Conclusion In conclusion, the allogeneic freeze-dried PL presented equivalent effects compared to frozen autologous PL. Intermediate platelet concentration on average demonstrated improved results, demonstrating less GAG loss compared to other concentrations.

scholarly journals Impact of the Different Preparation Methods to Obtain Autologous Non-Activated Platelet-Rich Plasma (A-PRP) and Activated Platelet-Rich Plasma (AA-PRP) in Plastic Surgery: Wound Healing and Hair Regrowth Evaluation

2020 ◽  
Vol 21 (2) ◽  
pp. 431 ◽  
Author(s):  
Pietro Gentile ◽  
Claudio Calabrese ◽  
Barbara De Angelis ◽  
Laura Dionisi ◽  
Jacopo Pizzicannella ◽  
...  
Keyword(s):  
Platelet Rich Plasma ◽  
Quality Criteria ◽  
Preparation Technique ◽  
Quality And Safety ◽  
Preparation Methods ◽  
Closed Technique ◽  
Sterile Processing

Autologous therapies using platelet-rich plasma (PRP) need meticulous preparation—currently, no standardised preparation technique exists. Processing Quantitative Standards (PQSs) define manufacturing quantitative variables (such as time, volume and pressure). Processing Qualitative Standards (PQLSs) define the quality of the materials and methods of manufacturing. The aim of this review is to use existing PQSs and PQLs to report the in vivo/in vitro results obtained by using different Kits, that utilise different procedures (classified as Closed-Technique and Opened-Technique) to isolate autologous human activated (AA-PRP) or non-activated PRP (A-PRP). PQSs included the volumes of blood collected as well as the reagents used, the time/gravity of centrifugation, and the duration, temperature and tilt level/speed of centrifugation. PQLSs included the use of Calcium Chloride CaCl2, Kit weight, transparency of Kit components, the maintenance of a closed sterile processing environment and the use of a small centrifuge. Eight CE marked devices for PRP extraction were evaluated: Angel®, Biomed®, Cascade® and Selphyl®, Mag-18®, i-Stem®, MyCells® and Regenlab®. Using a Kit with the PQSs and PQLSs described in this study enables the isolation of A-PRP, thereby meeting consensus quality criteria. As our understanding of Critical Quality Attributes (CQAs) of A-PRP continues to evolve, especially with respect to purity and potency, adjustments to these benchmark PQSs and PQLs will hopefully help isolate A-PRP of desired CQAs with greater reproducibility, quality, and safety. Confirmatory studies will no doubt need to be completed.

Comparison Of The Effects Of Aspirin In Humans Ex Vivo In Platelet-Rich Plasma And Whole Blood

1981 ◽  
Author(s):  
Barbara Nunn
Keyword(s):  
Whole Blood ◽  
Ex Vivo ◽  
Platelet Rich Plasma ◽  
Trisodium Citrate ◽  
Blood Platelet ◽  
Maximal Response ◽  
Blood Samples ◽  
Platelet Concentration

The effect of aspirin on human platelet function is usually assessed using platelet-rich plasma (PRP). Some preliminary results in vitro suggested that the effect of aspirin appears to be greater in PRP than whole blood. To explore this possibility further, a comparison of the effect of aspirin in humans ex vivo has been made taking measurements simultaneously in whole blood and PRP at 2 platelet concentrations. Blood samples (36ml) were drawn from 7 male volunteers after a light breakfast. Each took 300mg soluble aspirin and blood samples were drawn again 2 hours later. Blood was mixed with 0.1 volumes 129nM trisodium citrate. Some (30ml) was then centrifuged to prepare PRP and platelet -poor plasma (PPP) by standard techniques. Platelet concentration of some PRP was adjusted with PPP to equal that of the corresponding blood sample; the rest was adjusted to 350,000 per μl. Aggregation in response to collagen (Horm, Munich) was measured photometrically at 37°. Aggregation in 0.5ml aliquots of whole blood was measured after 4 min stirring with 154mM NaCl (control) or collagen at 37° as the fall in single platelet count determined using an Ultraflo- 100 whole blood platelet counter (Clay Adams). The concentrations of collagen producing a 50% maximal response (EC50) in PRP and blood were determined. Dose-ratios for each volunteer were calculated by dividing the EC50 obtained after aspirin by the corresponding value obtained before aspirin.The effect of aspirin was significantly (p<0.001) less in blood than PRP. Whether or not the results in whole blood more closely reflect the effect of aspirin in vivo remains to be determined.

scholarly journals A Critical Overview of the Use of Platelet-Rich Plasma in Equine Medicine Over the Last Decade

2021 ◽  
Vol 8 ◽  
Author(s):  
Livia Camargo Garbin ◽  
Catalina Lopez ◽  
Jorge U. Carmona
Keyword(s):  
Platelet Rich Plasma ◽  
Individual Variability ◽  
Therapeutic Effects ◽  
Clinical Use ◽  
Preparation Methods ◽  
Quantitative Evidence ◽  
Main Research ◽  
Anti Inflammatory

In the 1990s, the role of platelets in inflammation and tissue healing was finally recognized. Since then, the clinical use of platelet-derived products (hemocomponents), such as, platelet-rich plasma (PRP), markedly increased. The promise of a more economical option of a disease-modifying treatment led to the intensive and continuous research of PRP products and to its widespread clinical use. A number of protocols and commercial kits have been developed with the intention of creating a more practical and reliable option for clinical use in equine patients. Still, the direct comparison between studies is particularly challenging due to the lack of standardization on the preparation methods and product composition. The incomplete reports on PRP cellular concentration and the poorly designed in vivo studies are additional matters that contest the clinical efficiency of this biomaterial. To overcome such challenges, several in vitro and in vivo studies have been proposed. Specifically, experiments have greatly focused in protocol optimization and its effect in different tissues. Additionally, in vivo studies have proposed different biological products envisioning the upgrade of the anti-inflammatory cytokines trusting to increase its anti-inflammatory effect. The individual variability and health status of the animal, type of tissue and condition treated, and protocol implemented are known to influence on the product's cell and cytokine composition. Such variability is a main clinical concern once it can potentially influence on PRP's therapeutic effects. Thus, lack of qualitative and quantitative evidence-based data supporting PRP's clinical use persists, despite of the numerous studies intended to accomplish this purpose. This narrative review aims to critically evaluate the main research published in the past decade and how it can potentially impact the clinical use of PRP.

Plasma Microparticles Have Different Effects on Thrombin Generation in Platelet-Rich and Platelet-Poor Plasma.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1760-1760
Author(s):  
Gleb E. Ivanov ◽  
N. Macartney ◽  
E. Stephens ◽  
N. Bowen ◽  
S. Lees ◽  
...  
Keyword(s):  
Thrombin Generation ◽  
Platelet Rich Plasma ◽  
Maximal Velocity ◽  
Physiological Level ◽  
Wide Range ◽  
Coagulation Tests ◽  
Platelet Concentration ◽  
Vitro Effect ◽  
Free Plasma

Abstract Circulating peripheral blood microparticles (MPs) of various cell origin have been described and measured in physiological and a wide range of pathological conditions. MPs are likely to play a role in coagulation either by exposure of procoagulant phospholipids or expression of tissue factor (TF), but the degree of this contribution to global haemostasis is not yet clear. We studied thrombin generation (TG) parameters (lag, peak thrombin, initial velocity (Vini) and maximal velocity (Vmax) in platelet-free (PFP) and platelet-rich plasma (PRP) of normal volunteers (n=9) in presence of corn trypsin inhibitor, using calibrated automated thrombography (CAT). MP-rich plasma was prepared by ultracentrifugation of PFP and reconstitution of pelleted MPs in a reduced volume of autologous MP-free plasma. TG was also measured in MP-depleted supernatant and platelet-free plasma (PFP) filtered through 0.1 μm filter. In MP-rich plasma, triggered with 5pM TF, with no addition of exogenous phospholipids, we found significantly increased peak TG, compared with PFP and supernatant (70.8 +/− 6.3 vs 51.4 +/− 5.0 vs 28.4 +/− 2.2 nM/L thrombin, p=0.024 and p<0.0001 respectively). MP-rich fraction also produced raised Vini (10.3 +/− 0.9 vs 5.0 +/− 0.6 thrombin nM/L/min, p=0.019) and Vmax (18.3 +/− 2.4 vs 6.8 +/− 1.0 thrombin nM/L/min, p=0.004) compared with MP-depleted supernatant. Ultracentrifugation resulted in reduction of peak TG almost by half, compared with native PFP. The augmenting effect of MP-rich plasma on thrombin peak and velocity was shown to be abolished by filtration. In our experiments removal of MPs by filtration of PFP did not affect routine clinical coagulation tests, but resulted in a significant reduction of peak TG (from 51.4 +/− 5.0 to 23.9 +/− 1.4 thrombin nM, p=0.0002), Vini (from 10.2 +/− 0.4 to 5.6 +/− 0.6, p=0.02) and Vmax (from 15.2 +/− 1.8 to 5.9 +/− 0.2, p=0.02) as compared to PFP. In order to assess the contribution of MPs to TG in presence of platelets, MP-rich plasma was added to various dilutions of PRP, using low concentration of TF (0.5pM) as a trigger. Interestingly, addition of MP-rich fraction only marginally augmented PRP with a platelet concentration of 150x109/L, but the enhancement of peak and velocity of TG became more pronounced when platelet concentration was reduced to 1.5x109/L. In a separate set of experiments, we studied TG in PRP in which MP concentration was reduced by dilution with filtered MP-free plasma as compared to PRP diluted with MP-containing PFP. Reduction in PRP MP content did not lead to a significant decrease in TG even at a low platelet concentration (1.5x109/L), when MP concentration was reduced to about 100 times below the physiological level. Our results indicate that MPs contained in PFP of normal donors significantly affect thrombin generation peak and velocity when compared to PFP in which MPs were eliminated by either ultracentifugation or filtration. The in vitro effect of an increased number of MPs on TG is less noticeable in presence of near-physiological platelet count, but contribution of MPs to TG at low platelet concentrations may potentially protect from bleeding in thrombocytopenic states and explain differences in bleeding phenotype. CAT measurement of TG in MP-rich vs MP-poor plasma could serve as a useful tool in assessing these differences.

scholarly journals The optimal platelet concentration in platelet-rich plasma for proliferation of human cells in vitro—diversity, biases, and possible basic experimental principles for further research in the field: A review

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10303
Author(s):  
Olav K. Straum
Keyword(s):  
Human Cell ◽  
Platelet Rich Plasma ◽  
Human Cells ◽  
Proliferation Rate ◽  
In Vitro Studies ◽  
General Tendency ◽  
Platelet Concentration ◽  
Volume Group

Background In the last decades, several in vitro studies have tested the effect of plate-rich plasma (PRP) on the proliferation of human cells in search of a wizard for the use of PRP in a clinical setting. However, the literature displays striking differences regarding this question despite the relatively similar experimental design. The aim of this review is twofold: describe and explain this diversity and suggest basic principles for further in vitro studies in the field. The optimal platelet concentration in vivo will also be discussed. Methods A search in mainly EMBASE and PubMed was performed to identify in vitro studies that investigate the effect of different PRP concentrations on human cell proliferation. The assessment of bias was based on the principles of “Good Cell Culture Practice” and adapted. Results In total, 965 in vitro studies were detected. After the initial screening, 31 studies remained for full-text screening. A total of 16 studies met the criteria of final inclusion and appeared relatively sound. In general, the studies state consistently that PRP stimulates the proliferation of the human cell. Two main types of experimental techniques were detected: 1. The Fixed PRP Concentration Group using a fixed PRP concentration throughout the experiment, which leads to a substantial decrease in nutrition available at higher concentrations. 2. The Fixed PRP Volume Group using a fixed PRP-to-media ratio (Vol/Vol) throughout the experiment. A general tendency was observed in both groups: when the PRP to media ratio increased (Vol/Vol), the proliferation rate decreased. Further, The Low Leukocyte group observed a substantial higher optimal PRP concentration than The High leukocyte group. No prominent tendencies was seen regarding anticoagulants, activation methods, and blood donor (age or sex). Discussion Two major biases regarding optimal proliferation in vitro is pointed out: 1. Too high PRP volume. It is speculated that the techniques used by some studies led to an adverse growth condition and even cell starvation at higher concentrations. 2. High leukocyte levels. Reduced proliferation rate due to proinflammatory substances released during degranulation of leukocytes. Conclusions The two main biases may explain the bell-shaped effect of PRP and the detrimental effects at higher platelet concentrations observed in several studies. These biases may also explain the low optimal PRP concentration observed in some studies. Even if one universal optimal PRP concentration does not exist, the review indicates that PRP concentrations in the upper parts of the scale is optimal or at least beneficial. Finally, following basic experimental principles are suggested. 1: The PRP/media ratio (Vol/Vol) should be kept as constant. 2: The PRP/media ratio should provide a sufficient nutrition supply, that is, PRP ≤ 10% (Vol/Vol). 3: The cell density per well (cells/mL) should be defined. 4: Leukocyte level should be kept low, preferable depleted (< 0.1 PLT/µL).

scholarly journals Comparative Evaluation of the Angiogenic Potential of Hypoxia Preconditioned Blood-Derived Secretomes and Platelet-Rich Plasma: An In Vitro Analysis

Biomedicines ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 16 ◽  
Author(s):  
Philipp Moog ◽  
Katharina Kirchhoff ◽  
Sanjar Bekeran ◽  
Anna-Theresa Bauer ◽  
Sarah von Isenburg ◽  
...  
Keyword(s):  
Platelet Rich Plasma ◽  
Autologous Blood ◽  
Aortic Ring ◽  
Peripheral Blood Cell ◽  
Angiogenic Factor ◽  
Angiogenic Potential ◽  
Tissue Repair And Regeneration ◽  
Platelet Concentration ◽  
Vitro Analysis

Blood-derived factor preparations are being clinically employed as tools for promoting tissue repair and regeneration. Here we set out to characterize the in vitro angiogenic potential of two types of frequently used autologous blood-derived secretomes: platelet-rich plasma (PRP) and hypoxia preconditioned plasma (HPP)/serum (HPS). The concentration of key pro-angiogenic (VEGF) and anti-angiogenic (TSP-1, PF-4) protein factors in these secretomes was analyzed via ELISA, while their ability to induce microvessel formation and sprouting was examined in endothelial cell and aortic ring cultures, respectively. We found higher concentrations of VEGF in PRP and HPP/HPS compared to normal plasma and serum. This correlated with improved induction of microvessel formation by PRP and HPP/HPS. HPP had a significantly lower TSP-1 and PF-4 concentration than PRP and HPS. PRP and HPP/HPS appeared to induce similar levels of microvessel sprouting; however, the length of these sprouts was greater in HPP/HPS than in PRP cultures. A bell-shaped angiogenic response profile was observed with increasing HPP/HPS dilutions, with peak values significantly exceeding the PRP response. Our findings demonstrate that optimization of peripheral blood cell-derived angiogenic factor signalling through hypoxic preconditioning offers an improved alternative to simple platelet concentration and release of growth factors pre-stored in platelets.

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